Anvils incorporated in ultra-high pressure presses, such as cubic presses or belt presses, which are used in producing diamonds, polycrystalline diamond composites and cubic boron nitride, generate pressures in excess of 50 kilobars and are adjacent to press capsules having interior temperatures in excess of 1400° C. A typical anvil used in a cubic press is approximately 18 cm long with a base diameter of approximately 18 cm, but such anvils may be smaller or they may be significantly larger.
In order to apply uniform pressure, the working surface of the anvil should have a high hardness. As the hardness of the working surface of the anvil increases, the uniformity of the pressure applied by the anvil also increases. Suitable materials for forming the anvil include, for example, cemented tungsten carbide, which generally includes tungsten carbide particles dispersed in a cobalt matrix.